- Jul 15, 2021
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Sean Christopherson authored
Return -EFAULT if copy_to_user() fails; if accessing user memory faults, copy_to_user() returns the number of bytes remaining, not an error code. Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Cc: Steve Rutherford <srutherford@google.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Ashish Kalra <ashish.kalra@amd.com> Fixes: d3d1af85 ("KVM: SVM: Add KVM_SEND_UPDATE_DATA command") Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210506175826.2166383-2-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Maxim Levitsky authored
In theory there are no side effects of not intercepting #SMI, because then #SMI becomes transparent to the OS and the KVM. Plus an observation on recent Zen2 CPUs reveals that these CPUs ignore #SMI interception and never deliver #SMI VMexits. This is also useful to test nested KVM to see that L1 handles #SMIs correctly in case when L1 doesn't intercept #SMI. Finally the default remains the same, the SMI are intercepted by default thus this patch doesn't have any effect unless non default module param value is used. Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210707125100.677203-4-mlevitsk@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Maxim Levitsky authored
Kernel never sends real INIT even to CPUs, other than on boot. Thus INIT interception is an error which should be caught by a check for an unknown VMexit reason. On top of that, the current INIT VM exit handler skips the current instruction which is wrong. That was added in commit 5ff3a351 ("KVM: x86: Move trivial instruction-based exit handlers to common code"). Fixes: 5ff3a351 ("KVM: x86: Move trivial instruction-based exit handlers to common code") Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210707125100.677203-3-mlevitsk@redhat.com> Cc: stable@vger.kernel.org Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Maxim Levitsky authored
Commit 5ff3a351 ("KVM: x86: Move trivial instruction-based exit handlers to common code"), unfortunately made a mistake of treating nop_on_interception and nop_interception in the same way. Former does truly nothing while the latter skips the instruction. SMI VM exit handler should do nothing. (SMI itself is handled by the host when we do STGI) Fixes: 5ff3a351 ("KVM: x86: Move trivial instruction-based exit handlers to common code") Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210707125100.677203-2-mlevitsk@redhat.com> Cc: stable@vger.kernel.org Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Yu Zhang authored
vmx_msr_index was used to record the list of MSRs which can be lazily restored when kvm returns to userspace. It is now reimplemented as kvm_uret_msrs_list, a common x86 list which is only used inside x86.c. So just remove the obsolete declaration in vmx.h. Signed-off-by:
Yu Zhang <yu.c.zhang@linux.intel.com> Message-Id: <20210707235702.31595-1-yu.c.zhang@linux.intel.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Lai Jiangshan authored
When the host is using debug registers but the guest is not using them nor is the guest in guest-debug state, the kvm code does not reset the host debug registers before kvm_x86->run(). Rather, it relies on the hardware vmentry instruction to automatically reset the dr7 registers which ensures that the host breakpoints do not affect the guest. This however violates the non-instrumentable nature around VM entry and exit; for example, when a host breakpoint is set on vcpu->arch.cr2, Another issue is consistency. When the guest debug registers are active, the host breakpoints are reset before kvm_x86->run(). But when the guest debug registers are inactive, the host breakpoints are delayed to be disabled. The host tracing tools may see different results depending on what the guest is doing. To fix the problems, we clear %db7 unconditionally before kvm_x86->run() if the host has set any breakpoints, no matter if the guest is using them or not. Signed-off-by:
Lai Jiangshan <laijs@linux.alibaba.com> Message-Id: <20210628172632.81029-1-jiangshanlai@gmail.com> Cc: stable@vger.kernel.org [Only clear %db7 instead of reloading all debug registers. - Paolo] Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Ricardo Koller authored
Commit a75a895e ("KVM: selftests: Unconditionally use memslot 0 for vaddr allocations") removed the memslot parameters from vm_vaddr_alloc. It addressed all callers except one under lib/aarch64/, due to a race with commit e3db7579 ("KVM: selftests: Add exception handling support for aarch64") Fix the vm_vaddr_alloc call in lib/aarch64/processor.c. Reported-by:
Zenghui Yu <yuzenghui@huawei.com> Signed-off-by:
Ricardo Koller <ricarkol@google.com> Message-Id: <20210702201042.4036162-1-ricarkol@google.com> Reviewed-by:
Eric Auger <eric.auger@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Pavel Skripkin authored
In commit bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors") loop for filling debugfs_stat_data was copy-pasted 2 times, but in the second loop pointers are saved over pointers allocated in the first loop. All this causes is a memory leak, fix it. Fixes: bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors") Signed-off-by:
Pavel Skripkin <paskripkin@gmail.com> Reviewed-by:
Jing Zhang <jingzhangos@google.com> Message-Id: <20210701195500.27097-1-paskripkin@gmail.com> Reviewed-by:
Jing Zhang <jingzhangos@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Like Xu authored
The AMD platform does not support the functions Ah CPUID leaf. The returned results for this entry should all remain zero just like the native does: AMD host: 0x0000000a 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000 (uncanny) AMD guest: 0x0000000a 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00008000 Fixes: cadbaa03 ("perf/x86/intel: Make anythread filter support conditional") Signed-off-by:
Like Xu <likexu@tencent.com> Message-Id: <20210628074354.33848-1-likexu@tencent.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Kefeng Wang authored
BUG: KASAN: use-after-free in kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:183 Read of size 8 at addr ffff0000c03a2500 by task syz-executor083/4269 CPU: 5 PID: 4269 Comm: syz-executor083 Not tainted 5.10.0 #7 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x2d0 arch/arm64/kernel/stacktrace.c:132 show_stack+0x28/0x34 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x110/0x164 lib/dump_stack.c:118 print_address_description+0x78/0x5c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report+0x148/0x1e4 mm/kasan/report.c:562 check_memory_region_inline mm/kasan/generic.c:183 [inline] __asan_load8+0xb4/0xbc mm/kasan/generic.c:252 kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:183 kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3755 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Allocated by task 4269: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0xdc/0x120 mm/kasan/common.c:461 kasan_kmalloc+0xc/0x14 mm/kasan/common.c:475 kmem_cache_alloc_trace include/linux/slab.h:450 [inline] kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kvm_vm_ioctl_register_coalesced_mmio+0x78/0x1cc arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:146 kvm_vm_ioctl+0x7e8/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3746 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Freed by task 4269: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x38/0x6c mm/kasan/common.c:56 kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:355 __kasan_slab_free+0x124/0x150 mm/kasan/common.c:422 kasan_slab_free+0x10/0x1c mm/kasan/common.c:431 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook mm/slub.c:1577 [inline] slab_free mm/slub.c:3142 [inline] kfree+0x104/0x38c mm/slub.c:4124 coalesced_mmio_destructor+0x94/0xa4 arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:102 kvm_iodevice_destructor include/kvm/iodev.h:61 [inline] kvm_io_bus_unregister_dev+0x248/0x280 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:4374 kvm_vm_ioctl_unregister_coalesced_mmio+0x158/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:186 kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3755 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 If kvm_io_bus_unregister_dev() return -ENOMEM, we already call kvm_iodevice_destructor() inside this function to delete 'struct kvm_coalesced_mmio_dev *dev' from list and free the dev, but kvm_iodevice_destructor() is called again, it will lead the above issue. Let's check the the return value of kvm_io_bus_unregister_dev(), only call kvm_iodevice_destructor() if the return value is 0. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Message-Id: <20210626070304.143456-1-wangkefeng.wang@huawei.com> Cc: stable@vger.kernel.org Fixes: 5d3c4c79 ("KVM: Stop looking for coalesced MMIO zones if the bus is destroyed", 2021-04-20) Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Don't clear the C-bit in the #NPF handler, as it is a legal GPA bit for non-SEV guests, and for SEV guests the C-bit is dropped before the GPA hits the NPT in hardware. Clearing the bit for non-SEV guests causes KVM to mishandle #NPFs with that collide with the host's C-bit. Although the APM doesn't explicitly state that the C-bit is not reserved for non-SEV, Tom Lendacky confirmed that the following snippet about the effective reduction due to the C-bit does indeed apply only to SEV guests. Note that because guest physical addresses are always translated through the nested page tables, the size of the guest physical address space is not impacted by any physical address space reduction indicated in CPUID 8000_001F[EBX]. If the C-bit is a physical address bit however, the guest physical address space is effectively reduced by 1 bit. And for SEV guests, the APM clearly states that the bit is dropped before walking the nested page tables. If the C-bit is an address bit, this bit is masked from the guest physical address when it is translated through the nested page tables. Consequently, the hypervisor does not need to be aware of which pages the guest has chosen to mark private. Note, the bogus C-bit clearing was removed from legacy #PF handler in commit 6d1b867d ("KVM: SVM: Don't strip the C-bit from CR2 on #PF interception"). Fixes: 0ede79e1 ("KVM: SVM: Clear C-bit from the page fault address") Cc: Peter Gonda <pgonda@google.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: stable@vger.kernel.org Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210625020354.431829-3-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Ignore "dynamic" host adjustments to the physical address mask when generating the masks for guest PTEs, i.e. the guest PA masks. The host physical address space and guest physical address space are two different beasts, e.g. even though SEV's C-bit is the same bit location for both host and guest, disabling SME in the host (which clears shadow_me_mask) does not affect the guest PTE->GPA "translation". For non-SEV guests, not dropping bits is the correct behavior. Assuming KVM and userspace correctly enumerate/configure guest MAXPHYADDR, bits that are lost as collateral damage from memory encryption are treated as reserved bits, i.e. KVM will never get to the point where it attempts to generate a gfn using the affected bits. And if userspace wants to create a bogus vCPU, then userspace gets to deal with the fallout of hardware doing odd things with bad GPAs. For SEV guests, not dropping the C-bit is technically wrong, but it's a moot point because KVM can't read SEV guest's page tables in any case since they're always encrypted. Not to mention that the current KVM code is also broken since sme_me_mask does not have to be non-zero for SEV to be supported by KVM. The proper fix would be to teach all of KVM to correctly handle guest private memory, but that's a task for the future. Fixes: d0ec49d4 ("kvm/x86/svm: Support Secure Memory Encryption within KVM") Cc: stable@vger.kernel.org Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210623230552.4027702-5-seanjc@google.com> [Use a new header instead of adding header guards to paging_tmpl.h. - Paolo] Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Use boot_cpu_data.x86_phys_bits instead of the raw CPUID information to enumerate the MAXPHYADDR for KVM guests when TDP is disabled (the guest version is only relevant to NPT/TDP). When using shadow paging, any reductions to the host's MAXPHYADDR apply to KVM and its guests as well, i.e. using the raw CPUID info will cause KVM to misreport the number of PA bits available to the guest. Unconditionally zero out the "Physical Address bit reduction" entry. For !TDP, the adjustment is already done, and for TDP enumerating the host's reduction is wrong as the reduction does not apply to GPAs. Fixes: 9af9b940 ("x86/cpu/AMD: Handle SME reduction in physical address size") Cc: stable@vger.kernel.org Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210623230552.4027702-3-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Ignore the guest MAXPHYADDR reported by CPUID.0x8000_0008 if TDP, i.e. NPT, is disabled, and instead use the host's MAXPHYADDR. Per AMD'S APM: Maximum guest physical address size in bits. This number applies only to guests using nested paging. When this field is zero, refer to the PhysAddrSize field for the maximum guest physical address size. Fixes: 24c82e57 ("KVM: Sanitize cpuid") Cc: stable@vger.kernel.org Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210623230552.4027702-2-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Let KVM load if EFER.NX=0 even if NX is supported, the analysis and testing (or lack thereof) for the non-PAE host case was garbage. If the kernel won't be using PAE paging, .Ldefault_entry in head_32.S skips over the entire EFER sequence. Hopefully that can be changed in the future to allow KVM to require EFER.NX, but the motivation behind KVM's requirement isn't yet merged. Reverting and revisiting the mess at a later date is by far the safest approach. This reverts commit 8bbed95d. Fixes: 8bbed95d ("KVM: x86: WARN and reject loading KVM if NX is supported but not enabled") Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210625001853.318148-1-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Marc Zyngier authored
Commit b78f4a59 ("KVM: selftests: Rename vm_handle_exception") raced with a couple of new x86 tests, missing two vm_handle_exception to vm_install_exception_handler conversions. Help the two broken tests to catch up with the new world. Cc: Andrew Jones <drjones@redhat.com> CC: Ricardo Koller <ricarkol@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Marc Zyngier <maz@kernel.org> Message-Id: <20210701071928.2971053-1-maz@kernel.org> Reviewed-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Ricardo Koller <ricarkol@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini authored
Merge tag 'kvm-s390-master-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: selftests: Fixes - provide memory model for IBM z196 and zEC12 - do not require 64GB of memory
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- Jul 06, 2021
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Christian Borntraeger authored
Unless the user sets overcommit_memory or has plenty of swap, the latest changes to the testcase will result in ENOMEM failures for hosts with less than 64GB RAM. As we do not use much of the allocated memory, we can use MAP_NORESERVE to avoid this error. Cc: Zenghui Yu <yuzenghui@huawei.com> Cc: vkuznets@redhat.com Cc: wanghaibin.wang@huawei.com Cc: stable@vger.kernel.org Fixes: 309505dd ("KVM: selftests: Fix mapping length truncation in m{,un}map()") Tested-by:
Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/kvm/20210701160425.33666-1-borntraeger@de.ibm.com/ Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com>
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Christian Borntraeger authored
Older machines like z196 and zEC12 do only support 44 bits of physical addresses. Make this the default and check via IBC if we are on a later machine. We then add P47V64 as an additional model. Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Thomas Huth <thuth@redhat.com> Reviewed-by:
Cornelia Huck <cohuck@redhat.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/kvm/20210701153853.33063-1-borntraeger@de.ibm.com/ Fixes: 1bc603af ("KVM: selftests: introduce P47V64 for s390x")
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- Jun 25, 2021
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarmPaolo Bonzini authored
KVM/arm64 updates for v5.14. - Add MTE support in guests, complete with tag save/restore interface - Reduce the impact of CMOs by moving them in the page-table code - Allow device block mappings at stage-2 - Reduce the footprint of the vmemmap in protected mode - Support the vGIC on dumb systems such as the Apple M1 - Add selftest infrastructure to support multiple configuration and apply that to PMU/non-PMU setups - Add selftests for the debug architecture - The usual crop of PMU fixes
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Paolo Bonzini authored
Merge tag 'kvm-s390-next-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Features for 5.14 - new HW facilities for guests - make inline assembly more robust with KASAN and co
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Marc Zyngier authored
Last minute fix for MTE, making sure the pages are flagged as MTE before they are released. * kvm-arm64/mmu/mte: KVM: arm64: Set the MTE tag bit before releasing the page Signed-off-by:
Marc Zyngier <maz@kernel.org>
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Maxim Levitsky authored
This better reflects the purpose of this variable on AMD, since on AMD the AVIC's memory slot can be enabled and disabled dynamically. Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210623113002.111448-4-mlevitsk@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Aaron Lewis authored
When the kvm_intel module unloads the module parameter 'allow_smaller_maxphyaddr' is not cleared because the backing variable is defined in the kvm module. As a result, if the module parameter's state was set before kvm_intel unloads, it will also be set when it reloads. Explicitly clear the state in vmx_exit() to prevent this from happening. Signed-off-by:
Aaron Lewis <aaronlewis@google.com> Message-Id: <20210623203426.1891402-1-aaronlewis@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Reviewed-by:
Jim Mattson <jmattson@google.com>
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Aaron Lewis authored
This test exercises the feature KVM_CAP_EXIT_ON_EMULATION_FAILURE. When enabled, errors in the in-kernel instruction emulator are forwarded to userspace with the instruction bytes stored in the exit struct for KVM_EXIT_INTERNAL_ERROR. So, when the guest attempts to emulate an 'flds' instruction, which isn't able to be emulated in KVM, instead of failing, KVM sends the instruction to userspace to handle. For this test to work properly the module parameter 'allow_smaller_maxphyaddr' has to be set. Signed-off-by:
Aaron Lewis <aaronlewis@google.com> Reviewed-by:
Jim Mattson <jmattson@google.com> Message-Id: <20210510144834.658457-3-aaronlewis@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Aaron Lewis authored
Add a fallback mechanism to the in-kernel instruction emulator that allows userspace the opportunity to process an instruction the emulator was unable to. When the in-kernel instruction emulator fails to process an instruction it will either inject a #UD into the guest or exit to userspace with exit reason KVM_INTERNAL_ERROR. This is because it does not know how to proceed in an appropriate manner. This feature lets userspace get involved to see if it can figure out a better path forward. Signed-off-by:
Aaron Lewis <aaronlewis@google.com> Reviewed-by:
David Edmondson <david.edmondson@oracle.com> Message-Id: <20210510144834.658457-2-aaronlewis@google.com> Reviewed-by:
Jim Mattson <jmattson@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Let the guest use 1g hugepages if TDP is enabled and the host supports GBPAGES, KVM can't actively prevent the guest from using 1g pages in this case since they can't be disabled in the hardware page walker. While injecting a page fault if a bogus 1g page is encountered during a software page walk is perfectly reasonable since KVM is simply honoring userspace's vCPU model, doing so arguably doesn't provide any meaningful value, and at worst will be horribly confusing as the guest will see inconsistent behavior and seemingly spurious page faults. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-55-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Use the current MMU instead of vCPU state to query CR4.SMEP when handling a page fault. In the nested NPT case, the current CR4.SMEP reflects L2, whereas the page fault is shadowing L1's NPT, which uses L1's hCR4. Practically speaking, this is a nop a NPT walks are always user faults, i.e. this code will never be reached, but fix it up for consistency. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-54-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Use the current MMU instead of vCPU state to query CR0.WP when handling a page fault. In the nested NPT case, the current CR0.WP reflects L2, whereas the page fault is shadowing L1's NPT. Practically speaking, this is a nop a NPT walks are always user faults, but fix it up for consistency. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-53-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Drop the extra reset of shadow_zero_bits in the nested NPT flow now that shadow_mmu_init_context computes the correct level for nested NPT. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-52-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Drop the pre-computed last_nonleaf_level, which is arguably wrong and at best confusing. Per the comment: Can have large pages at levels 2..last_nonleaf_level-1. the intent of the variable would appear to be to track what levels can _legally_ have large pages, but that intent doesn't align with reality. The computed value will be wrong for 5-level paging, or if 1gb pages are not supported. The flawed code is not a problem in practice, because except for 32-bit PSE paging, bit 7 is reserved if large pages aren't supported at the level. Take advantage of this invariant and simply omit the level magic math for 64-bit page tables (including PAE). For 32-bit paging (non-PAE), the adjustments are needed purely because bit 7 is ignored if PSE=0. Retain that logic as is, but make is_last_gpte() unique per PTTYPE so that the PSE check is avoided for PAE and EPT paging. In the spirit of avoiding branches, bump the "last nonleaf level" for 32-bit PSE paging by adding the PSE bit itself. Note, bit 7 is ignored or has other meaning in CR3/EPTP, but despite FNAME(walk_addr_generic) briefly grabbing CR3/EPTP in "pte", they are not PTEs and will blow up all the other gpte helpers. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-51-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Expand the comments for the MMU roles. The interactions with gfn_track PGD reuse in particular are hairy. Regarding PGD reuse, add comments in the nested virtualization flows to call out why kvm_init_mmu() is unconditionally called even when nested TDP is used. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-50-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Replace make_spte()'s WARN on a collision with the magic MMIO value with a generic WARN on reserved bits being set (including EPT's reserved WX combination). Warning on any reserved bits covers MMIO, A/D tracking bits with PAE paging, and in theory any future goofs that are introduced. Opportunistically convert to ONCE behavior to avoid spamming the kernel log, odds are very good that if KVM screws up one SPTE, it will botch all SPTEs for the same MMU. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-49-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Extract the reserved SPTE check and print helpers in get_mmio_spte() to new helpers so that KVM can also WARN on reserved badness when making a SPTE. Tag the checking helper with __always_inline to improve the probability of the compiler generating optimal code for the checking loop, e.g. gcc appears to avoid using %rbp when the helper is tagged with a vanilla "inline". No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-48-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Use the MMU's role instead of vCPU state or role_regs to determine the PTTYPE, i.e. which helpers to wire up. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-47-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Skip paging32E_init_context() and paging64_init_context_common() and go directly to paging64_init_context() (was the common version) now that the relevant flows don't need to distinguish between 64-bit PAE and 32-bit PAE for other reasons. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-46-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Add a helper to calculate the level for non-EPT page tables from the MMU's role_regs. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-45-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Consolidate MMU guest metadata updates into a common helper for TDP, shadow, and nested MMUs. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-44-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Don't bother updating the bitmasks and last-leaf information if paging is disabled as the metadata will never be used. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-43-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Move calls to reset_rsvds_bits_mask() out of the various mode statements and under a more generic CR0.PG=1 check. This will allow for additional code consolidation in the future. No functional change intended. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-42-seanjc@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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